Antimicrobial agents obtained by reacting N-substituted propylenediamines with 2-aminoglutaric acid esters are known from DE-A1 3410956 (Henkel). The amides formed in this reaction, which are marketed as Glucoprotamin.RTM., may optionally be derivatized with alkylene oxides and/or acids. An overview of the antimicrobial properties of these substances was published in Hyg. Med. 17, 529 (1992). In addition, the use of Glucoprotamin.RTM. as a virucidal agent is known from DE-A1 4340124 (Ecolab).
Unfortunately, the known aminoglutaric acid ester amides have the disadvantage that concentrates, i.e. aqueous preparations thereof with an active substance content of about 20 to 50% by weight, are often neither color-stable nor storage-stable. On the contrary, the concentrates tend to thicken in storage, to separate crystals and to turn cloudy.
Accordingly, the complex problem addressed by the present invention was to provide a simple process by which glucoprotamines with excellent color quality, which would combine a low viscosity after dilution with water with improved storage stability, could be obtained in a high yield and selectivity.